Histoplasmosis

About

Histoplasmosis is an infection caused by the fungus Histoplasma capsulatum. The fungus lives in the environment in the central and eastern United States, parts of Central and South America, and other areas of the world. People can get histoplasmosis after breathing in the microscopic fungal spores from the air, although most people who inhale the spores don’t get sick.

Histoplasmosis sometimes affects healthy people, but the infection often goes away without antifungal medication. However, histoplasmosis can be very serious in people who have weakened immune systems, such as people with cancer or HIV/AIDS. In Latin America, histoplasmosis is one of the most common infections among people with HIV/AIDS, and the mortality rate ranges from 20 to 40%.

Symptoms

The signs and symptoms of histoplasmosis are very similar to those of other respiratory infections such as tuberculosis (TB), which may lead to delays in diagnosing and treating histoplasmosis appropriately.

Diagnosis and Treatment

The standard methods available to diagnose histoplasmosis, such as culture or histopathology, often require invasive procedures to obtain a sample for testing. In addition, culture can take days to weeks to produce results, and histopathology has limited sensitivity, meaning it doesn’t always detect the infection. Some antifungal medications to treat histoplasmosis are not widely available or are very expensive.

Enzyme-linked immunosorbent assay (ELISA) can detect Histoplasma antigen in urine, and is potentially faster, less expensive, and more sensitive than traditional diagnostic methods. Earlier, more reliable diagnosis of histoplasmosis can:

• Minimize delays in treatment and prevent deaths
• Save money and resources spent looking for alternate diagnoses, and
• Reduce unnecessary treatment for other suspected illnesses.